1. Field of the Invention
The present invention relates to a method for manufacturing a magnetic head. To be more specific, it relates to a manufacturing method that is suited for performing fine machining on the air bearing surfaces of a magnetic head.
2. Discussion of Background
For this type of magnetic head, it is sometimes necessary to perform fine machining on the air bearing surfaces in order to set the width of the pole portions in the direction of the tracks, to achieve the desired electromagnetic conversion characteristics and flight attitude and the like. For instance, Japanese Unexamined Patent Publication (KOKAI) Nos. 274014/1992 and 274008/1992 disclose a technology to set the width of the pole portions in the direction of the tracks with high precision and to improve the electromagnetic conversion characteristics by providing an indented portion of minute depth at one end of the air bearing surfaces in the direction of the width of the pole portions or in the direction of the thickness (length) of the pole portions.
Also, the TPC (Transverse Pressure Contour) type sliders which are disclosed in Japanese Unexamined Patent Publication (KOKAI) No. 278087/1986, Japanese Unexamined Utility Model Publication (KOKAI) No. 122063/1982 (Utility Model Application No. 5815/1981), U.S. Pat. No. 4,673,996, U.S. Pat. No. 4,870,519 and the like, require fine machining in order to form a minute step portion or a tapered portion at a side of the rail portions. A TPC slider, when mounted in a rotary actuator type magnetic disk device, generates dynamic lift pressure at the step portion with the airflow coming in from the transverse direction at positions where the skew angle is large and, with this, any reduction in the flying height at positions where the skew angle is large is prevented so that a constant flying height is assured overall and so that the flight attitude is stabilized.
A known means for performing the fine machining described above on the air bearing surfaces involves adhering an organic resist on the air bearing surface, performing patterning on this resist so that it will have a pattern corresponding to the machining required and then performing ion milling or the like using the resist that remains after the patterning and that functions as a protective film. Prior art literature that discloses such technology includes Japanese Unexamined Patent Publication (KOKAI) Nos. 190215/1991 and 212811/1991. Of these, Japanese Unexamined Patent Publication (KOKAI) No. 190215/1991 discloses a technology that employs the spin-coat method and Japanese Unexamined Patent Publication (KOKAI) No. 212811/1991 discloses a technology that employs a jig for dry etching machining.
Generally speaking, when the spin-coat method is employed, resist liquid collects on the edge portion which faces opposite the direction of the rotation, making the thickness of the resist film inconsistent. In order to solve this problem, Japanese Unexamined Patent Publication (KOKAI) No. 190215/1991 discloses a technology through which the thickness of the resist film is made consistent by making the substrate that is used for the slider of the magnetic head incline by grinding off an edge. This grinding requirement is one of the problems of the prior art technology.
In the case of Japanese Unexamined Patent Publication (KOKAI) No. 212811/1991, which employs a jig for dry etching machining, a high degree of dimensional precision is required for the difference in the levels of the steps of the object of machining and the jig in order to improve the accuracy of the film thickness. In addition, the machining precision on the object of machining performed prior to the insertion into the jig must also be high. These factors increase the cost of production.